diff --git a/assets/bg_core.jpg b/assets/bg/bg_core.jpg
similarity index 100%
rename from assets/bg_core.jpg
rename to assets/bg/bg_core.jpg
diff --git a/assets/bg_earth.jpg b/assets/bg/bg_earth.jpg
similarity index 100%
rename from assets/bg_earth.jpg
rename to assets/bg/bg_earth.jpg
diff --git a/assets/bg_sky.jpg b/assets/bg/bg_sky.jpg
similarity index 100%
rename from assets/bg_sky.jpg
rename to assets/bg/bg_sky.jpg
diff --git a/assets/bg_star.jpg b/assets/bg/bg_star.jpg
similarity index 100%
rename from assets/bg_star.jpg
rename to assets/bg/bg_star.jpg
diff --git a/assets/bg_under.jpg b/assets/bg/bg_under.jpg
similarity index 100%
rename from assets/bg_under.jpg
rename to assets/bg/bg_under.jpg
diff --git a/assets/bg/world_bg_keyart_16x9.png b/assets/bg/world_bg_keyart_16x9.png
deleted file mode 100644
index 95c1070..0000000
Binary files a/assets/bg/world_bg_keyart_16x9.png and /dev/null differ
diff --git a/assets/bg/world_bg_keyart_16x9_clean.png b/assets/bg/world_bg_keyart_16x9_clean.png
deleted file mode 100644
index 5c9bde1..0000000
Binary files a/assets/bg/world_bg_keyart_16x9_clean.png and /dev/null differ
diff --git a/world.html b/world.html
index 95767bb..4d18dbd 100644
--- a/world.html
+++ b/world.html
@@ -684,11 +684,11 @@ const LAYER_BG = {
 // 大地、天空按四个时间节点各配一段视频；星空、地下、地心各一段、不随时间变
 // 每个世界固定一段背景视频；时间线只改色调（currentPalette.tint 叠加），不切换视频
 const WORLDS = [
-  { id:'star',  name:'星空', icon:'✦',  image:'assets/bg_star.jpg' },
-  { id:'sky',   name:'天空', icon:'🌤', image:'assets/bg_sky.jpg' },
-  { id:'earth', name:'大地', icon:'🌍', image:'assets/bg_earth.jpg', sandbox:true },
-  { id:'under', name:'地下', icon:'🕳', image:'assets/bg_under.jpg' },
-  { id:'core',  name:'地心', icon:'🔥', image:'assets/bg_core.jpg' },
+  { id:'star',  name:'星空', icon:'✦',  image:'assets/bg/bg_star.jpg' },
+  { id:'sky',   name:'天空', icon:'🌤', image:'assets/bg/bg_sky.jpg' },
+  { id:'earth', name:'大地', icon:'🌍', image:'assets/bg/bg_earth.jpg', sandbox:true },
+  { id:'under', name:'地下', icon:'🕳', image:'assets/bg/bg_under.jpg' },
+  { id:'core',  name:'地心', icon:'🔥', image:'assets/bg/bg_core.jpg' },
 ];